1. Technical Field
This disclosure relates generally to profiling subroutines executing on a processor, and more specifically, to identifying and correlating trace data associated with executing subroutines.
2. Description of the Related Art
Developers of processors and/or applications usually need to have access to a basic set of development tool functions in order to accomplish their jobs. For run-control, a developer typically needs to query and modify when a processor is halted, showing all locations available in a supervisor map of the processor. Moreover, a developer also usually needs support for breakpoint/watchpoint features in debuggers, either as hardware or software breakpoints depending on the architecture. For logic analysis, a developer usually needs to access instruction trace information. A developer typically needs to be able to interrogate and correlate instruction flow to real-world interactions. A developer also usually needs to retrieve information on how data flows through the system and to understand what system resources are creating and accessing data. Additionally, a developer usually needs to assess whether embedded software is meeting a required performance level.
The Nexus 5001 Forum (formerly known as the global embedded processor debug interface standard consortium (GEPDISC)) was formed to develop an embedded debug/trace interface standard (the “Nexus standard”) for embedded control applications. The Nexus standard is particularly applicable to the development of automotive powertrains, data communication equipment, computer peripherals, wireless systems, and other control applications. The Nexus standard provides a specification and guidelines for implementing various messages, e.g., program trace messages (such as branch history messages and synchronization messages), data trace messages, and task/process identification messages (such as ownership trace messages), that may be utilized in debugging applications while minimally impacting operation of a system under development. As defined by the Nexus standard, a program trace message is a message that is provided in response to a change of program flow. According to the Nexus standard, a data trace message is a message that provides visibility of a target processor when a memory write/read reference is detected that matches debug logic data trace attributes. The Nexus standard also defines an ownership trace message (OTM) as a message that provides a macroscopic view of a processor that may be used for task flow reconstruction when debugging software that is written in a high-level language.